Absorbent article comprising a liquid handling member having high suction and high permeability

ABSTRACT

It is one aspect of the present invention to provide a liquid handling member which combines high liquid suction capability with a high permeability. It is another aspect of the present invention to provide liquid handling member which combines a high liquid suction capability with a fast 80 percent capacity absorption time. The present invention further provides devices for handling body liquids which comprise the liquid handling member of the present invention such as for example baby diapers, training pants, sanitary napkins, adult incontinence devices, bed mats, and the like.

FIELD OF THE INVENTION

The present invention relates to devices for managing body fluids suchas urine, sweat, saliva, blood, menses, purulence, or fecal material,and in particular to their ability to acquire and retain aqueous basedmaterials. The invention further relates to disposable absorbentarticles such as baby diapers or training pants, adult incontinenceproducts, and feminine hygiene products and other body liquid handlingarticles such as catheters, urinals, and the like.

The invention further relates to devices for managing body liquidscomprising a liquid handling member having high suction and highpermeability.

BACKGROUND

Devices for managing body fluids are well known in the art and arefrequently used for a wide variety of purposes. For example, the devicesserve hygienic purposes such as diapers, sanitary napkins, adultincontinence products, underarm sweat pads, and the like. There isanother class of such devices which serve medical purposes such as wounddressings or drainages, catheters, and the like. Accordingly suchdevices have been designed to cope with a large variety of differentbody liquids such as for example urine, sweat, saliva, blood, menses,purulence, fecal material, and the like.

The ability to provide better performing devices such as diapers hasbeen contingent on the ability to develop relatively thin absorbentcores or structures that can acquire and store large quantities ofdischarged body fluids, in particular urine.

In addition, it is preferred to provide structures having a low capacityin the regions between the legs of the wearer such as in PCT applicationU.S. Ser. No. 97-05046, filed on Mar. 27, 1997, relating to the movementof fluid through certain regions of the article comprising materialshaving good acquisition and distribution properties to other regionscomprising materials having specific liquid storage capabilities.

Most of the absorbent articles comprise therefore at least one fluidhandling member that is designed for quickly acquiring and/ortransporting liquid away from the loading point.

Examples of suitable liquid transport members based on crosslinked andcurled cellulose are disclosed in European patent application No. 0 512010 (Cook et al.). Further examples of suitable liquid transport membershaving high vertical liquid transport rates are disclosed in Europeanpatent application No. 0 809 991 (Schmidt et al.). Other suitable liquidtransport members based on HIPE foams are disclosed in U.S. patentapplication Ser. No. 09-042418 (DesMarais et al., P&G case 7051).

Example structures comprising liquid transport members to transportliquid out of the crotch region are disclosed in PCT patent applicationWO 98/43580 (LaVon et al.).

Whilst such liquid transport members have been designed with capillarytransport mechanisms in mind, thus aiming at positioning materials withsmaller capillaries and/or increased hydrophilicity closer to theultimate storage material, and materials with larger pores and lesshydrophilicity closer to the loading zone, it has in addition beenrecognized, that acquisition/distribution materials have the tendency tonot only transport the fluid, but also to retain the liquid, which canresult under specific conditions to undesired effects, such as rewet orreduced fluid acquisition and/or distribution performance, which isparticularly pronounced for acquisition/distribution materials beingdesigned to balance acquisition and distribution properties.

Accordingly, liquid storage members have been developed, which have animproved balance of the fluid handling properties such that wellperforming acquisition/distribution materials or members can bedewatered efficiently by the storage materials or members. This istypically achieved by fluid storage materials or members having a highliquid suction capability.

In PCT patent application No. U.S. Ser. No. 98105044 (Palumbo et al.),absorbent structures are disclosed which comprise materials exhibiting ahigh liquid suction capability. These materials disclosed by the priorart employ small capillaries such as obtained by a small capillary HIPEfoam, a mixture of superabsorber and high surface area fibers and thelike to provide the high liquid suction capability. These structureshave, however, the disadvantage that the small capillaries limit theliquid permeability thus providing large flow resistance and slow ratefor liquid being absorbed.

Hence, it is an object of the present invention to provide a liquidhandling member which overcomes the problems posed by the prior art.

It is a further object of the present invention to provide a liquidhandling member which exhibits a high liquid suction capability incombination with a high liquid permeability and/or a high absorbentrate.

It is a further object of the present invention to provide a device forhandling body liquids comprising a liquid handling member which exhibitsa high liquid suction capability in combination with a high liquidpermeability and/or a high absorbent rate.

SUMMARY OF THE INVENTION

The present invention provides a liquid handling member to be used in adevice for handling by liquids.

The liquid handling member is characterized in that said liquid handlingmember has a capillary sorption absorption height at 50% of its capacityat 0 cm absorption height (CSAH50) according to the capillary sorptiontest of at least 50 cm and said liquid handling member further having aliquid permeability of at least 5 Darcy preferably at least 10 Darcy,most preferably at least 20 Darcy according to the saturated liquidpermeability test.

Attentively, the liquid handling member is characterized in that saidliquid handling member has a capillary sorption absorption height at 50%of its capacity at 0 cm absorption height (CSAH50) according to thecapillary sorption test of at least 80 cm and said liquid handlingmember further having a liquid permeability of at least 2 Darcyaccording to the saturated liquid permeability test.

Yet alternatively, the liquid handling member is characterized in thatsaid liquid handling member has a capillary sorption absorption heightat 50% of its capacity at 0 cm absorption height (CSAH50) according tothe capillary sorption test of at least 80 cm and said liquid handlingmember further having an absorption time to 80% of its capacity of lessthan 5 seconds according to the Demand Absorbency Test disclosed herein.

The liquid handling member preferably has a capillary sorptionabsorption capacity at 100 cm absorption height of at least 5 g/g,preferably at least 10 g/g.

The invention further relates to absorbent structures, comprising afirst region for acquisition/distribution of fluid and a second regionfor storage of fluid. The first region comprises at least one member foracquiring and/or transporting liquid whereas the second region comprisessaid liquid handling members.

The present invention further provides a device for handling bodyliquids comprising a liquid handling member or an absorbent structureaccording to the present invention. The present invention furtherrelates to absorbent articles such as baby diapers comprising a liquidhandling member or an absorbent structure according to the presentinvention.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1, 2A and 2B show a schematic drawing of the setup for the liquidpermeability test.

FIG. 3 shows a schematic drawing of the setup for the capillary sorptiontest.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is described in the following by means of avariety of different embodiments and by means of a variety of differentfeatures. Further embodiments of the present invention may be obtainedby combining features of one embodiment with features of anotherembodiment disclosed herein and/or with other features disclosed herein.These further embodiments are considered to be implicitly disclosedherein and hence form part of the present invention. It will be apparentto the skilled person that combinations of certain features may lead tonon-functional articles not forming part of this present invention.

The present invention provides liquid handling members to be used indevices for handling body liquids. The present invention furtherprovides devices for handling body liquids which comprise the liquidhandling member of the present invention such as for example babydiapers, training pants, sanitary napkins, adult incontinence devices,bed mats, and the like.

The term “handling body liquid” includes but is not limited toacquiring, distributing, and storing body liquid.

It is one aspect of the present invention to provide a liquid handlingmember which combines high liquid suction capability with a high liquidpermeability. In the context of the present invention, the term “liquidpermeability” includes both in-plane and transplanar permeability.Saturated liquid permeability of a liquid handling member in the contextof the present invention is defined in the saturated state, i.e. whenthe member has absorbed at least 90% of its capacity. It will be clearto the man skilled in the art that a high liquid permeability throughoutthe entire absorbent cycle is desired. In one embodiment of the presentinvention it is therefore preferred, that the liquid handling membersexhibit high liquid permeability both in the saturated as well in theunsaturated state. The high liquid suction capability allows that wellperforming acquisition/distribution materials or members can bedewatered efficiently by the storage materials or members. A high liquidpermeability in in-plane as well as transplanar direction allowsefficient distribution of the acquired body liquids within the liquidhandling member of the present invention, in particular distributionagainst gravity and relatively high flux rates.

For the purpose of this invention, trans-planar permeability isquantified by the permeability test defined hereinafter. It isrecognized, however, that members having high in-plane permeability arealso part of the scope of the present invention. The liquid handlingmember of the present invention has a permeability of at least 2 Darcy,preferably at least 5 Darcy, more preferably at least 10 Darcy, and mostpreferably a permeability of at least 20 Darcy.

It is another aspect of the present invention to provide liquid handlingmember which combines a high liquid suction capability with a fastabsorption rate such as for example expressed by a fast absorption timeto 80% capacity in the demand absorbency test. A fast 80 percentcapacity absorption time is representative of the ability of liquidhandling member to efficient be used the majority of its absorbentcapacity in a fast and efficient way in order to avoid that the liquidstorage becomes the rate limiting step for the performance of thedevice.

For the purpose of this invention, liquid suction is quantified by thecapillary sorption test defined hereinafter. The liquid handling memberof the present invention has a capillary Sorption Absorption Height at50% of its capacity at 0 centimeter absorption height of at least 50centimeter, preferably of at least 80 cm , more preferably of at least100 cm.

For the purpose of this invention, the 80 percent capacity absorptiontime is quantified by the demand absorbency test defined hereinafter.The liquid handling member of the present invention has a 80 percentabsorption time of less than 5 seconds, preferably a 80 percentabsorption time of less than 2 second, more preferably of less than 1.5seconds, most preferably of less than 1 second.

It is another aspect of the present invention to provide a liquidhandling member having a capillary absorption capacity of at least 5g/g, preferably at least 10 g/g at a high hydrostatic height of at least50 cm , preferably at least 100 cm. A high absorbent capacity allowsstorage of larger quantities of body liquids such as for example urinegushes.

In the following, a suitable embodiment of the liquid handling memberwill be described. The liquid handling member is assembled from an innermaterial which is completely enveloped by a membrane. Suitable membranematerials are available from SEFAR of Ruischlikon, Switzerland, underthe designation SEFAR 03-10/2 and under the designation SEFAR 03-5/1. Asuitable foam material for use as inner material is available fromRecticel of Brussels, Belgium, under the designation Bulpren S10 black.Other suitable inner materials may be obtained by punching holes of 2 mmdiameter at a density of about 2 holes per square centimeter intomaterials available from Fisher Scientific of Germany, under thedesignation D&N Pelleus ball size 5 and under the designation D&NPelleus ball size 7. A suitable technique to completely envelope thefoam material with the membrane material is to wrap the membranematerial around the foam material and to subsequently heat seal all openedges of the membrane material. It will be readily apparent to theskilled practitioner to choose other similarly suitable materials.Depending on the specific intended application of the liquid handlingmember, it may also be required to choose similar materials withslightly different properties. After assembly, the liquid handlingmember is activated by immersing the liquid handling member in water orin synthetic urine until the liquid handling member is completely filledwith liquid and until the membranes are completely wetted with liquid.After activation, a part of-the liquid inside the liquid handling membermay be squeezed out by applying an external pressure to the liquidhandling member. If the activation of the liquid handling member wassuccessful, the liquid handling member should not suck air through themembranes.

Other liquid handling members suitable for the purposes of the presentinvention are described for example in the PCT patent application No.PCT/US98/13497 entitled “Liquid transport member for high flux ratesbetween two port regions” filed in the name of Ehrnsperger et al. filedon Jun. 29, 1998, and in the following PCT patent applications co-filedwith the present application entitled “High flux liquid transportmembers comprising two different permeability regions” (P&G caseCM1840MQ) filed in the name of Ehrnsperger et al., “Liquid transportmember for high flux rates between two port regions” (P&G case CM1841MQ)filed in the name of Ehrnsperger et al., “Liquid transport member forhigh flux rates against gravity” (P&G case CM1842MQ) filed in the nameof Ehmsperger et al., “Liquid transport member having high permeabilitybulk regions and high bubble point pressure port regions” (P&G caseCM1843MQ) filed in the name of Ehrnsperger et al. All of these documentsare enclosed herein by reference.

The particular geometry of the liquid handling member of the presentinvention can be varied according to the specific requirements off theintended application. If, for example, the liquid handling member isintended to be used in an absorbent article the liquid handling membermay be defined such that its zone of intended liquid acquisition fitsbetween the legs of the wearer and further that its intended liquiddischarge zone matches the form of the storage member associated to it.Accordingly, the outer dimensions of the liquid handling member such aslength, width, or thickness may also be adapted to the specific needs ofthe intended application. In this context, it has to be understood,however, that the design of the outer form of the liquid handling membermay have an impact on its performance.

In one embodiment of the present invention, the liquid handling memberof the present invention is geometrically saturated or substantiallygeometrically saturated with free liquid. The term “free liquid” as usedherein refers to liquid which is not bound to a specific surface orother entity. Free liquid can be distinguished from bound liquid bymeasuring the proton spin relaxation time T₂ of the liquid molecules aaccording to NMR (nuclear magnetic resonance) spectroscopy methods wellknown in the art.

The term “geometrically saturated” as used herein refers to a region ofa porous material in which the liquid accessible void spaces have beenfilled with a liquid. The void spaces referred to in this definition arethose which are present in the current geometric configuration of theporous material. In other words, a geometrically saturated device maystill be able to accept additional liquid by and only by changing itsgeometric configuration for example by swelling, although all voids ofthe device are filled with liquid in the current geometricconfiguration. A device for handling liquids is called geometricallysaturated, if all porous materials that are part of the device andintended for liquid handling are geometrically saturated.

The term “porous material” as used herein refers to materials thatcomprise at least two phases a solid material and a gas or void phaseand optionally a third liquid phase that may be partially or completelyfilling said void spaces. The porosity of a material is defined as theratio between the void volume and the total volume of the material,measured when the material is not filled with liquid. Non-limitingexamples for porous materials are foams such as polyurethane, HIPE (seefor example PCT patent application WO94/13704), superabsorbent foams andthe like, fiber assemblies such as meltblown, spunbond, carded,cellulose webs, fiber beds and the like, porous particles such as clay,zeolites, and the like, geometrically structured materials such astubes, balloons, channel structures etc. Porous materials might absorbliquids even if they are not hydrophilic. The porosity of the materialsis therefore not linked to their affinity for the liquid that might beabsorbed.

The term “substantially geometrically saturated” as used herein refersto a member in which at least 90% of the macroscopic void volume of themember are geometrically saturated, preferably at least 95% of themacroscopic void volume of the device are geometrically saturated, morepreferably 97% of the macroscopic void volume of the device aregeometrically saturated, most preferably 99% of the macroscopic voidvolume of the device are geometrically saturated.

It is another aspect of the present invention to provide an absorbentstructure comprising a first region for acquisition/distribution offluid and a second region for storage of fluid. The first regioncomprises at least one member for acquiring and/or transporting liquidsuch those well known in the art. The second region comprises a liquidhandling member according to the present invention.

Device for Handling Body Liquid

It is one aspect of the present invention to provide a device forhandling body liquids which comprises a liquid transport memberaccording to the present invention and/or an absorbent structureaccording to the present invention. Such devices include but are notlimited to disposable absorbent articles such as baby diapers ortraining pants, adult incontinence products, and feminine hygieneproducts and other body liquid handling articles such as catheters,urinals, and the like.

In one embodiment of the present invention, the device for handling bodyliquids is a disposable absorbent article such as a diaper, a trainingpant, a sanitary napkin, an adult incontinence device, or the like thatcomprises the liquid handling member of the present invention. Such anabsorbent article may further comprise a liquid pervious topsheet, aliquid impervious backsheet at least partially peripherally joined tothe topsheet. The absorbent article may further comprise a first liquidhandling member which may serve as a acquisition and/or distributionmember for the body liquid. Topsheets, backsheet, and absorbent coressuitable for the present invention are well known in the art. Inaddition, there are numerous additional features known in the art whichcan be used in combination with the absorbent article of the presentinvention such as for example closure mechanisms to attach the absorbentarticle around the lower torso of the wearer.

Methods

Unless stated otherwise, all tests are carried out at about 32° C. +/−2°C. and at 35+/−15% relative humidity.

Unless stated otherwise, the synthetic urine used in the test methods iscommonly known as Jayco SynUrine and is available from JaycoPharmaceuticals Company of Camp Hill, Pa. The formula for the syntheticurine is: 2.0 g/: of KCl; 2.0 g/l of Na2SO4; 0.85 g/l of (NH4)H2PO4;0.15 g/l (NH4)H2PO4; 0.19 g/l of CaCl2; ad 0.23 g/l of MgCl2. All of thechemicals are of reagent grade. The pH of the synthetic Urine is in therange of 6.0 to 6.4.

Capillary Sorption Test

Purpose

The purpose of this test is to measure the capillary sorption absorbentcapacity, as a function of height, of liquid handling members of thepresent invention. This test may also be used to measure the capillarysorption absorbent capacity of devices for handling body liquidsaccording to the present invention. Capillary sorption is a fundamentalproperty of any absorbent that governs how liquid is absorbed into theabsorbent structure. In the Capillary Sorption experiment, capillarysorption absorbent capacity is measured as a function of fluid pressuredue to the height of the sample relative to the test fluid reservoir.

The method for determining capillary sorption is well recognized. SeeBurgeni, A. A. and Kapur, C., “Capillary Sorption Equilibria in FiberMasses,” Textile Research Journal, 37 (1967), 356-366; Chatterjee, P.K., Absorbency, Textile Science and Technology 7, Chapter II, pp 29-84,Elsevier Science Publishers B. V, 1985; and U.S. Pat. No. 4,610,678,issued Sep. 9, 1986 to Weisman et al. for a discussion of the method formeasuring capillary sorption of absorbent structures. The disclosure ofeach of these references is incorporated by reference herein.

Principle

A porous glass frit is connected via an uninterrupted column of fluid toa fluid reservoir on a balance. The sample is maintained under aconstant confining weight during the experiment. As the porous structureabsorbs fluid upon demand, the weight loss in the balance fluidreservoir is recorded as fluid uptake, adjusted for uptake of the glassfrit as a function of height and evaporation. The uptake or capacity atvarious capillary suctions (hydrostatic tensions or heights) ismeasured. Incremental absorption occurs due to the incremental loweringof the frit (i.e., decreasing capillary suction).

Time is also monitored during the experiment to enable calculation ofinitial effective uptake rate (g/g/h) at a 200 cm height.

Reagents

Test Liquid: Synthetic urine is prepared by completely dissolving thefollowing materials in distilled water.

Compound F.W. Concentration (g/L) KCI 74.6 2.0 Na₂SO₄ 142 2.0 (NH₄)H₂PO₄115 0.85 (NH₄)₂HPO₄ 132 0.15 CaCl₂.2H₂O 147 0.25 MgCl₂.6H₂O 203 0.5

General Description of Apparatus Set Up

The Capillary Sorption equipment, depicted generally as 520 in FIG. 3,used for this test is operated under TAPPI conditions (50% RH, 25° C.).A test sample is placed on a glass frit shown in FIG. 3 as 502 that isconnected via a continuous column of test liquid (synthetic urine) to abalance liquid reservoir, shown as 506, containing test liquid. Thisreservoir 506 is placed on a balance 507 that is interfaced with acomputer (not shown). The balance should be capable of reading to 0.001g; such a balance is available from Mettler Toledo as PR1203(Hightstown, N.J.). The glass frit 502 is placed on a vertical slide,shown generally in FIG. 3 as 501, to allow vertical movement of the testsample to expose the test sample to varying suction heights. Thevertical slide may be a rodless actuator which is attached to a computerto record suction heights and corresponding times for measuring liquiduptake by the test sample. A preferred rodless actuator is availablefrom Industrial Devices (Novato, Calif.) as item202X4X34N-1D4B-84-P-C-S-E, which may be powered by motor drive ZETA6104-83-135, available from CompuMotor (Rohnert, Calif.). Where data ismeasured and sent from actuator 501 and balance 507, capillary sorptionabsorbent capacity data may be readily generated for each test sample.Also, computer interface to actuator 501 may allow for controlledvertical movement of the glass frit 502. For example, the actuator maybe directed to move the glass frit 502 vertically only after“equilibrium” (as defined below) is reached at each suction height.

The bottom of glass frit 502 is connected to TygonÒ tubing 503 thatconnects the frit 505 to three-way drain stopcock 509. Drain stopcock509 is connected to liquid reservoir 505 via glass tubing 504 andstopcock 510. (The stopcock 509 is open to the drain only duringcleaning of the apparatus or air bubble removal.) Glass tubing 511connects fluid reservoir 505 with balance fluid reservoir 506, viastopcock 510. Balance liquid reservoir 506 may consist of a lightweight12 cm diameter glass dish 506A and cover 506B. The cover 506B has a holethrough which glass tubing 511 contacts the liquid in the reservoir 506.The glass tubing 511 must not contact the cover 506B or an unstablebalance reading will result and the test sample measurement cannot beused. In this context, it is to be understood that the volume of theliquid reservoir needs to be compatible with the absorbent capacity ofthe liquid handing member or the device to be tested. Hence, it may benecessary to choose a different liquid reservoir.

The glass frit diameter must be sufficient to accommodate thepiston/cylinder apparatus, discussed below, for holding the test sample.The glass frit 502 is jacketed to allow for a constant temperaturecontrol from a heating bath. A suitable frit is a 350 ml fritted discfunnel specified as having 4 to 5.5 mm pores, available from CorningGlass Co. (Corning, N.Y.) as #36060-350F. The pores are fine enough tokeep the frit surface wetted at capillary suction heights specified (theglass frit does not allow air to enter the continuous column of testliquid below the glass frit).

As indicated, the frit 502 is connected via tubing to fluid reservoir505 or balance liquid reservoir 506, depending on the position ofthree-way stopcock 510.

Glass frit 502 is jacketed to accept water from a constant temperaturebath. This will ensure that the temperature of the glass frit is kept ata constant temperature of 88° F. (31° C.) during the testing procedure.As is depicted in FIG. 3, the glass frit 502 is equipped with an inletport 502A and outlet port 502B, which make a closed loop with acirculating heat bath shown generally as 508. (The glass jacketing isnot depicted in FIG. 3. However, the water introduced to the jacketedglass frit 502 from bath 508 does not contact the test liquid and thetest liquid is not circulated through the constant temperature bath. Thewater in the constant temperature bath circulates through the jacketedwalls of the glass frit 502.)

Reservoir 506 and balance 507 are enclosed in a box to minimizeevaporation of test liquid from the balance reservoir and to enhancebalance stability during performance of the experiment. This box, showngenerally as 512, has a top and walls, where the top has a hole throughwhich tubing 511 is inserted.

The glass frit 502 is shown in more detail in FIG. 2B. FIG. 2B is across-sectional view of the glass frit, shown without inlet port 502Aand outlet port 502B. As indicated, the glass frit is a 350 ml fritteddisc funnel having specified 4 to 5.5 mm pores. Referring to FIG. 2B,the glass frit 502 comprises a cylindrical jacketed funnel designated as550 and a glass frit disc shown as 560. The glass frit 502 furthercomprises a cylinder/piston assembly shown generally as 565 (whichcomprises cylinder 566 and piston 568), which confines the test sample,shown as 570, and provides a small confining pressure to the testsample. To prevent excessive evaporation of test liquid from the glassfrit disc 560, a Teflon ring shown as 562 is placed on top of the glassfrit disc 560. The TeflonÒ ring 562 is 0.0127 cm thick (available assheet stock from McMasterCarr as # 8569K16 and is cut to size) and isused to cover the frit disc surface outside of the cylinder 566, andthus minimizes evaporation from the glass frit. The ring outer diameterand inner diameter is 7.6 and 6.3 cm , respectively. The inner diameterof the Teflon® ring 562 is about 2 mm less than the outer diameter ofcylinder 566. A Viton® O-ring (available from McMasterCarr as #AS568A-150 and AS56BA-151) 564 is placed on top of Teflon® ring 562 toseal the space between the inner wall of cylindrical jacketed funnel 550and Teflon® ring 562, to further assist in prevention of evaporation. Ifthe O-ring outer diameter exceeds the inner diameter of cylindricaljacketed funnel 550, the O-ring diameter is reduced to fit the funnel asfollows: the O-ring is cut open, the necessary amount of O-ring materialis cut off, and the O-ring is glued back together such that the O-ringcontacts the inner wall of the cylindrical jacketed funnel 550 allaround its periphery. While the above described frit represents onesuitable example of frit, it may be necessary to use of frit havingdimensions different from the above dimensions in order to better fitthe dimensions of the liquid handling member or the device to be tested.The surface area of the frit should resemble as closely as possible thesurface area of the acquisition zone of the liquid handling member orthe device in order to fully use the acquisition zone and in order tominimize the evaporation from the frit.

As indicated, a cylinder/piston assembly shown generally in FIG. 2B as565 confines the test sample and provides a small confining pressure tothe test sample 570. Referring to FIG. 2C, assembly 565 consists of acylinder 566, a cup-like TeflonÒ piston indicated by 568 and, whennecessary, a weight or weights (not shown) that fits inside piston 568.(Optional weight will be used when necessary to adjust the combinedweight of the piston and the optional weight so a confining pressure of0.2 psi is attained depending on the test sample's dry diameter. This isdiscussed below.) The cylinder 566 is LexanÒ bar stock and has thefollowing dimensions: an outer diameter of 7.0 cm diameter of 6.0 cm anda height of 6.0 cm. The TeflonÒ piston 568 has the following dimensions:an outer diameter that is 0.02 cm less than the inner diameter ofcylinder 566. As shown in FIG. 2D, the end of the piston 568 that doesnot contact the test sample is bored to provide a 5.0 cm diameter byabout 1.8 cm deep chamber 590 to receive optional weights (dictated bythe test sample's actual dry diameter) required to attain a test sampleconfining pressure of 0.2 psi (1.4 kPa). In other words, the totalweight of the piston 568 and any optional weights (not shown in figures)divided by the test sample's actual diameter (when dry) should be suchthat a confining pressure of 0.2 psi is attained. Cylinder 566 andpiston 568 (and optional weights) are equilibrated at 31° C. for atleast 30 minutes prior to conducting the capillary sorption absorbentcapacity measurement. Again, the above described dimensions are chosento fit the above described exemplary frit. Of course, when a differentfrit is chosen the dimensions of the cylinder/piston assembly need to beadjusted accordingly.

A non-surfactant treated or incorporated apertured film (14 cm×14 cm )(not shown) is used to cover the glass frit 502 during CapillarySorption experiments to minimize air destablization around the sample.Apertures are large enough to prevent condensation from forming on theunderside of the film during the experiment.

Test Sample Preparation

For the present procedure, it is important, that the dimensions of thesample and of the frit should not be too different. To achieve this, twoapproaches can be taken:

a) For test samples, which can be readily adjusted to a suitable size,such as by cutting these, both the size of this cutting as well as ofthe frit are chosen to be a circular shaped structure of 5.4 cmdiameter, such as can be done by using a conventional arc punch.

b) When the test sample cannot readily be cut to this dimension, thesize and preferably also the shape of the frit has to be adjusted to thesize and shape of the test sample.

In both cases, the test sample can be a readily separable element of amember or a device, it can be a particular component of any of these, orcan be a combination of components thereof. It might also be necessaryto adjust the size of the liquid reservoir to match the varyingrequirements.

The dry weight of the test sample (used below to calculate capillarysorption absorbent capacity) is the weight of the test sample preparedas above under ambient conditions.

Experimental Set Up

1. Place a clean, dry glass frit 502 in a funnel holder attached to thevertical slide 501. Move the funnel holder of the vertical slide suchthat the glass frit is at the 0 cm height.

2. Set up the apparatus components as shown in FIG. 3, as discussedabove.

3. Place 12 cm diameter balance liquid reservoir 506 on the balance 507.Place plastic lid 506B over this balance liquid reservoir 506 and aplastic lid over the balance box 512 each with small holes to allow theglass tubing 511 to fit through. Do not allow the glass tubing to touchthe lid 506B of the balance liquid reservoir or an unstable balancereading will result and the measurement cannot be used.

4. Stopcock 510 is closed to tubing 504 and opened to glass tubing 511.Fluid reservoir 505, previously filled with test fluid, is opened toallow test fluid to enter tubing 511, to fill balance fluid reservoir506.

5. The glass frit 502 is leveled and secured in place. Also, ensure thatthe glass frit is dry.

6. Attach the TygonÒ tubing 503 to stopcock 509. (The tubing should belong enough to reach the glass frit 502 at its highest point of 200 cmwith no kinks.) Fill this TygonÒ tubing with test liquid from liquidreservoir 505.

7. Attach the TygonÒ tubing 503 to the level glass frit 502 and thenopen stopcock 509 and stopcock 510 leading from fluid reservoir 505 tothe glass frit 502. (Stopcock 510 should be closed to glass tubing 511.)The test liquid fills the glass frit 502 and removes all trapped airduring filling of the level glass frit. Continue to fill until the fluidlevel exceeds the top of the glass frit disc 560. Empty the funnel andremove all air bubbles in the tubing and inside the funnel. Air bubblesmay be removed by inverting glass frit 502 and allowing air bubbles torise and escape through the drain of stopcock 509. (Air bubblestypically collect on the bottom of the glass frit disc 560.) Relevel thefrit using a small enough level that it will fit inside the jacketedfunnel 550 and onto the surface of glass frit disc 560.

8. Zero the glass frit with the balance liquid reservoir 506. To dothis, take a piece of TygonÒ tubing of sufficient length and fill itwith the test liquid. Place one end in the balance liquid reservoir 506and use the other end to position the glass frit 502. The test liquidlevel indicated by the tubing (which is equivalent to the balance liquidreservoir level) is 10 mm below the top of the glass frit disc 560. Ifthis is not the case, either adjust the amount of liquid in thereservoir or reset the zero position on the vertical slide 501.

9. Attach the outlet and inlet ports from the temperature bath 508 viatubing to the inlet and outlet ports 502A and 502B, respectively, of theglass frit. Allow the temperature of the glass frit disc 560 to come to31° C. This can be measured by partially filling the glass frit withtest liquid and measuring its temperature after it has reachedequilibrium temperature. The bath will need to be set a bit higher than31° C. to allow for the dissipation of heat during the travel of waterfrom the bath to the glass frit.

10. The glass frit is equilibrated for 30 minutes.

Capillary Somtion Parameters

The following describes a computer program that will determine how longthe glass frit remains at each height.

In the capillary sorption software program, a test sample is at somespecified height from the reservoir of fluid. As indicated above, thefluid reservoir is on a balance, such that a computer can read thebalance at the end of a known time interval and calculate the flow rate(Delta reading/time interval) between the test sample and reservoir. Forpurposes of this method, the test sample is considered to be atequilibrium when the flow rate is less than a specified flow rate for aspecified number of consecutive time intervals. It is recognized, thatfor certain material, actual equilibrium may not be reached when thespecified “EQUILIBRIUM CONSTANT” is reached. The time interval betweenreadings is 5 seconds.

The number of readings in the delta table is specified in the capillarysorption menu as “EQUILIBRIUM SAMPLES”. The maximum number of deltas is500. The flow rate constant is specified in the capillary sorption menuas “EQUILIBRIUM CONSTANT”.

The Equilibrium Constant is entered in units of grams/sec, ranging from0.0001 to 100.000.

The following is a simplified example of the logic. The table shows thebalance reading and Delta Flow calculated for each Time Interval.

Equilibrium Samples=3

Equilibrium Constant = 0.0015 Balance Delta Time Value Flow Interval (g)(g/sec) 0 0 1 0.090 0.0180 2 0.165 0.0150 3 0.225 0.0120 4 0.270 0.00905 0.295 0.0050 6 0.305 0.0020 7 0.312 0.0014 8 0.316 0.0008 9 0.3180.0004

DELTA TABLE Time 0 1 2 3 4 5 6 7 8 9 Delta 1 9999 0.0180 0.0180 0.01800.0090 0.0090 0.0090 0.0014 0.0014 0.0014 Delta 2 9999 9999 0.01500.0150 0.0150 0.0050 0.0050 0.0050 0.0008 0.0008 Delta 3 9999 9999 99990.0120 0.0120 0.0120 0.0020 0.0020 0.0020 0.0004

The equilibrium uptake for the above simplified example is 0.318 gram.

The following is the code in C language used to determine equilibriumuptake:

/*   takedata.c  */ int take_data(int equil_samples,doubleequilibrium_constant) { double delta; static double deltas[500]; /*table to store up to 500 deltas */ double value; double prev_value;clock_t next_time; int  i; for (i=0; i<equil_samples; i++) deltas[i] =9999.; /* initialize all values in the delta table to 9999. gms/sec */delta_table_index = 0; /* initialize where in the table to store thenext delta */ equilibrium_reached = 0; /* initialize flag to indicateequilibrium has not been reached */ next_time = clock(); /* initializewhen to take the next reading */ prev_reading = 0.; /* initialize thevalue of the previous reading from the balance */ while(!equilibrium_reached) { /* start of loop for checking for equilibrium*/ next_time += 5000L; /* calculate when to take next reading */ while(clock() < next_time); /* wait until 5 seconds has elapsed from prevreading */ value = get_balance__reading(); /* read the balance in grams*/ delta = fabs(prev_value − value) /5.0; /* calculate absolute value offlow in last 5 seconds */ prev_value = value; /* store current value fornext loop */ deltas[delta_table_index] = delta; */ store current deltavalue in the table of deltas */ delta_table_index++; /* incrementpointer to next position in table */ if (delta_table_index ==equil_samples) /* when the number of deltas = the number of */delta_table_index = 0; /* equilibrium samples /* specified, reset the *//* pointer to the start of */ /* the table. This way the */ /* tablealways contains the */ /* last xx current samples. */equilibrium_reached = 1; /* set the flag to indicate equilibrium isreached */ for (i=0; i<equil_samples; i++) /* check all the values inthe delta table */ if (deltas[i] >= equilibrium_constant) /* if anyvalue is > or = to the equilibrium constant */ equilibrium_reached = 0;/* set the equilibrium flag to 0 (not at equilibrium) */ } /* go back tothe start of the loop */ }

Capillary Sorption Parameters

Load Description (Confining Pressure): 0.2 psi load

Equilibrium Samples (n): 50

Equilibrium Constant: 0.0005 g/sec

Setup Height Value: 100 cm

Finish Height Value: 0 cm

Hydrostatic Head Parameters: 200, 180, 160, 140, 120, 100, 90, 80, 70,60, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5 and 0 cm.

The capillary sorption procedure is conducted using all the heightsspecified above, in the order stated, for the measurement of capillarysorption absorbent capacity. Even if it is desired to determinecapillary sorption absorbent capacity at a particular height (e.g., 35cm ), the entire series of hydrostatic head parameters must be completedin the order specified. Although all these heights are used inperformance of the capillary sorption test to generate capillarysorption isotherms for a test sample, the present disclosure describesthe storage absorbent members in terms of their absorbent properties atspecified heights of 200, 140, 100, 50, 35 and 0 cm.

Caipillary Sormtion Procedure

1) Follow the experimental setup procedure.

2) Make sure the temperature bath 508 is on and water is circulatingthrough the glass frit 502 and that the glass frit disc 560 temperatureis 31° C.

3) Position glass frit 502 at 200 cm suction height. Open stopcocks 509and 510 to connect glass frit 502 with the balance liquid reservoir 506.(Stopcock 510 is closed to liquid reservoir 505.) Glass frit 502 isequilibrated for 30 minutes.

4) Input the above capillary sorption parameters into the computer.

5) Close stopcocks 509 and 510.

6) Move glass frit 502 to the set up height, 100 cm.

7) Place Teflon® ring 562 on surface of glass frit disc 560. Put O-ring564 on Teflon® ring. Place pre-heated cylinder 566 concentrically on theTeflon® ring. Place test sample 570 concentrically in cylinder 566 onglass frit disc 560. Place piston 568 into cylinder 566. Additionalconfining weights are placed into piston chamber 590, if required.

8) Cover the glass frit 502 with apertured film.

9) The balance reading at this point establishes the zero or tarereading.

10) Move the glass frit 502 to 200 cm.

11) Open stopcocks 509 and 510 (stopcock 510 is closed to fluidreservoir 505) and begin balance and time readings.

Glass Frit Correction (blank correct uptake)

Since the glass frit disc 560 is a porous structure, the glass frit(502) capillary sorption absorption uptake (blank correct uptake) mustbe determined and subtracted to get the true test sample capillarysorption absorption uptake. The glass frit correction is performed foreach new glass frit used. Run the capillary sorption procedure asdescribed above, except without test sample, to obtain the Blank Uptake(g). The elapsed time at each specified height equals the Blank Time(s).

Evaporation Loss Correction

1) Move the glass frit 502 to 2 cm above zero and let it equilibrate atthis height for 30 minutes with open stopcocks 509 and 510 (closed toreservoir 505).

2) Close stopcocks 509 and 510.

3) Place Teflon® ring 562 on surface of glass frit disc 560. Put O-ring564 on Teflon® ring. Place pre-heated cylinder 566 concentrically on theTeflon® ring. Place piston 568 into cylinder 586. Place apertured filmon glass frit 502.

4) Open stopcocks 509 and 510 (closed to reservoir 505) and recordbalance reading and time for 3.5 hours. Calculate Sample Evaporation(g/hr) as follows:

[balance reading at 1 hr—balance reading at 3.5 hr] 12.5 hr.

Even after taking all the above precautions, some evaporative loss willoccur, typically around 0.10 gm/hr for both the test sample and the fritcorrection. Ideally, the sample evaporation is measured for each newlyinstalled glass frit 502.

Cleaning the Equipment New TygonÒ tubing 503 is used when a glass frit502 is newly installed. Glass tubing 504 and 511, fluid reservoir 505,and balance liquid reservoir 506 are cleaned with 50% Clorox Bleach® indistilled water, followed by distilled water rinse, if microbialcontamination is visible.

a. Cleaning After Each Experiment

At the end of each experiment (after the test sample has been removed),the glass frit is forward flushed (i.e., test liquid is introduced intothe bottom of the glass frit) with 250 ml test liquid from liquidreservoir 505 to remove residual test sample from the glass frit discpores. With stopcocks 509 and 510 open to liquid reservoir 505 andclosed to balance liquid reservoir 506, the glass frit is removed fromits holder, turned upside down and is rinsed out first with test liquid,followed by rinses with acetone and test liquid (synthetic urine).During rinsing, the glass frit must be tilted upside down and rinsefluid is squirted onto the test sample contacting surface of the glassfrit disc. After rinsing, the glass frit is forward flushed a secondtime with 250 ml test liquid (synthetic urine). Finally, the glass fritis reinstalled in its holder and the frit surface is leveled.

b. Monitoring Glass Frit Performance

Glass frit performance must be monitored after each cleaning procedureand for each newly installed glass frit, with the glass frit set up at 0cm position. 50 ml of test liquid are poured onto the leveled glass fritdisc surface (without Teflon® ring, O-ring and the cylinder/pistoncomponents). The time it takes for the test fluid level to drop to 5 mmabove the glass frit disc surface is recorded. A periodic cleaning mustbe performed if this time exceeds 4.5 minutes.

c. Periodic Cleaning

Periodically, (see monitoring frit performance, above) the glass fritsare cleaned thoroughly to prevent clogging. Rinsing fluids are distilledwater, acetone, 50% Clorox Bleach® in distilled water (to removebacterial growth) and test liquid. Cleaning involves removing the glassfrit from the holder and disconnecting all tubing. The glass frit isforward flushed (i.e., rinse liquid is introduced into the bottom of theglass frit) with the frit upside down with the appropriate fluids andamounts in the following order:

1. 250 ml distilled water.

2. 100 ml acetone.

3. 250 ml distilled water.

4. 100 ml 50:50 Clorox®/distilled water solution.

5. 250 ml distilled water.

6. 250 ml test fluid.

The cleaning procedure is satisfactory when glass frit performance iswithin the set criteria of fluid flow (see above) and when no residue isobservable on the glass frit disc surface. If cleaning can not beperformed successfully, the frit must be replaced.

Calculations

The computer is set up to provide a report consisting of the capillarysuction height in cm, time, and the uptake in grams at each specifiedheight. From this data, the capillary suction absorbent capacity, whichis corrected for both the frit uptake and the evaporation loss, can becalculated. Also, based on the capillary suction absorbent capacity at 0cm , the capillary absorption efficiency can be calculated at thespecified heights. In addition, the initial effective uptake rate at 200cm is calculated.

Blank Correct Uptake$\text{Blank Correct Uptake (g)} = {\text{Blank Uptake (g)} - \frac{\text{Blank Time (s)}*\text{Blank Evap. (g/hr)}}{\text{3600 (s/hr)}}}$

Capillary Suction Absorbent Capacity (“CSAC”)$\text{Net Uptake (g/g)} = \frac{\text{Sample Uptake (g)} - \frac{\text{Sample Time (s)}*\text{Sample Evap. (g/hr)}}{\text{3600 s/hr}} - \text{Blank Correct Uptake (g)}}{\text{Dry Weight of Sample (g)}}$

Initial Effective Uptake Rate at 200 cm (“IEUR”)

IEUR (g/g/hr)=CSAC at 200 cm (g/g)

Sample Time at 200 cm (s)

Reporting

A minimum of two measurements should be taken for each sample and theuptake averaged at each height to calculate Capillary Sorption AbsorbentCapacity (CSAC) for a given absorbent member or a given high surfacearea material.

With these data, the respective values can be calculated:

The Capillary Sorption Desorption Height at which the material hasreleased x% of its capacity at 0 cm (i.e. of CSAC 0), (CSDH x) expressedin cm;

The Capillary Sorption Absorption Height at which the material hasabsorbed y% of its capacity at 0 cm (i.e. of CSAC 0), (CSAH y) expressedin cm;

The Capillary Sorption Absorbent Capacity at a certain height z (CSAC z)expressed in units of g {of fluid}/g { of material}; especially at theheight zero (CSAC 0), and at heights of 35 cm , 40 cm , etc

The Capillary Sorption Absorption Efficiency at a certain height z (CSAEz) expressed in %, which is the ratio of the values for CSAC 0 and CSACz.

If two materials are combined (such as the first being used asacquisition/distribution material, and the second being used as liquidstorage material), the CSAC value (and hence the respective CSAE value)of the second material can be determined for the CSDH x value of thefirst material.

Demand Absorbency Test

The demand absorbency test is intended to measure the liquid capacity ofliquid handling member and to measure the absorption speed of liquidhandling member against zero hydrostatic pressure. The test may also becarried out for devices for managing body liquids containing a liquidhandling member.

The apparatus used to conduct this test consists of a square basket of asufficient size to hold the liquid handling member suspended on a frame.At least the lower plane of the square basket consists of an open meshthat allows liquid penetration into the basket without substantial flowresistance for the liquid uptake. For example, an open wire mesh made ofstainless steel having an open area of at least 70 percent and having awire diameter of 1 mm, and an open mesh size of at about 6 mm issuitable for the setup of the present test. In addition, the open meshshould exhibit sufficient stability such that it substantially does notdeform under load of the test specimen when the test specimen is filledup to its full capacity.

Below the basket, a liquid reservoir is provided. The height of thebasket can be adjusted so that a test specimen which is placed insidethe basket may be brought into contact with the surface of the liquid inthe liquid reservoir. The liquid reservoir is placed on theelectronic-balance connected to a computer to read out the weight of theliquid about every 0.01 sec during the measurement. The dimensions ofthe apparatus are chosen such that the liquid handling member to betested fits into the basket and such that the intended liquidacquisition zone of the liquid handing member is in contact with thelower plane of the basket. The dimensions of the liquid reservoir arechosen such that the level of the liquid surface in the reservoir doesnot substantially change during the measurement. A typical reservoiruseful for testing liquid handling members has a size of at least 320mm×370 mm and can hold at least about 4500 g of liquid.

Before the test, the liquid reservoir is filled with synthetic urine.The amount of synthetic urine and the size of the liquid reservoirshould be sufficient such that the liquid level in the reservoir doesnot change when the liquid capacity of the liquid handing member to betested is removed from the reservoir.

The temperature of the liquid and the environment for the test shouldreflect in-use conditions of the member. Typical temperature for use inbaby diapers are 32 degrees Celsius for the environment and 37 degreesCelsius for the synthetic urine. The test may be done at roomtemperature if the member tested has no significant dependence of itsabsorbent properties on temperature.

The test is setup by lowering the empty basket until the mesh is justcompletely immersed in the synthetic urine in the reservoir. The basketis then raised again by about 0.5 to 1 mm in order to establish analmost zero hydrostatic suction, care should be taken that the liquidstays in contact with the mesh. If necessary, the mesh needs to bebrought back into contact with the liquid and zero level be readjusted.

The test is started by:

1. starting the measurement of the electronic balance;

2. placing the liquid handling member on the mesh such that theacquisition zone of the member is in contact with the liquid;

3. immediately adding a low weigh on top of the member in order toprovide a pressure of 165 Pa for better contact of the member to themesh.

During the test, the liquid uptake by the liquid handing member isrecorded by measuring the weight decrease of the liquid in the liquidreservoir. The test is stopped after 30 minutes.

At the end of the test, the total liquid uptake of the liquid handlingmember is recorded. In addition, the time after which the liquidhandling member had absorbed 80 percent of its total liquid uptake isrecorded. The zero time is defined as the time where the absorption ofthe member starts. The initial absorption speed of the liquid handlingmember is from the initial linear slope of the weight vs. timemeasurement curve.

Saturated Liquid Permeability Test

In order to measure the saturated liquid permeability, the liquidpermeability test as described below is executed with the test samplebeing at 100% saturation. Saturation in this context is defined as thetest sample having absorbed 100% of its capacity that it has in thedemand absorbency test.

Generally, the test can be carried out with a suitable test fluidrepresenting the transport fluid, such as with Jayco SynUrine asavailable from Jayco Pharmaceuticals Company of Camp Hill, Pa., and canbe operated-under controlled laboratory conditions of about 23 +/−2° C.and at 50+/−10% relative humidity. However, when using polymeric foammaterials, such as disclosed in U.S. Pat. No. 5,563,179 or U.S. Pat. No.5,387,207, it has been found more useful to operate the test at anelevated temperature of 31° C., and by using de-ionized water as testfluid.

In principle, this tests is based on Darcy's law, according to which thevolumetric flow rate of a liquid through any porous medium isproportional to the pressure gradient, with the proportionality constantrelated to permeability.

Q/A=(k/η)*(ΔP/L)

where:

Q=Volumetric Flow Rate [cm³/s];

A=Cross Sectional Area [cm²];

k=Permeability (cm²) (with 1 Darcy corresponding to 9.869* 10⁻¹³ m²);

η=Viscosity (Poise) [Pa*s];

ΔP/L=Pressure Gradient [Pa/m];

L=caliper of sample [cm].

Hence, permeability can be calculated—for a fixed or given samplecross-sectional area and test liquid viscosity—by measurement ofpressure drop and the volumetric flow rate through the sample:

k=(Q/A)*(L/ΔP)*η

The test can be executed in two modifications, the first referring tothe transplanar permeability (i.e. the direction of flow is essentiallyalong the thickness dimension of the material), the second being thein-plane permeability (i.e. the direction of flow being in thex-y-direction of the material).

The test set-up for the transplanar permeability test can be see in FIG.1 which is a schematic diagram of the overall equipment and—as an insertdiagram—a partly exploded cross-sectional, not to scale view of thesample cell.

The test set-up comprises a generally circular or cylindrical samplecell (19120), having an upper (19121) and lower (19122) part. Thedistance of these parts can be measured and hence adjusted by means ofeach three circumferentially arranged caliper gauges (19145) andadjustment screws (19140). Further, the equipment comprises severalfluid reservoirs (19150, 19154, 19156) including a height adjustment(19170) for the inlet reservoir (19150) as well as tubings (19180),quick release fittings (19189) for connecting the sample cell with therest of the equipment, further valves (19182, 19184, 19186, 19188). Thedifferential pressure transducer (19197) is connected via tubing (19180)to the upper pressure detection point (I9194) and to the lower pressuredetection point (19196). A Computer device (19190) for control of valvesis further connected via connections (19199) to differential pressuretransducer (19197), temperature probe (19192), and weight scale loadcell (19198).

The circular sample (19110) having a diameter of 1 in (about 2.54 cm )is placed in between two porous screens (19135) inside the sample cell(19120), which is made of two 1 in (2.54 cm ) inner diameter cylindricalpieces (19121, 19122) attached via the inlet connection (19132) to theinlet reservoir (19150) and via the outlet connection (19133) to theoutlet reservoir (19154) by flexible tubing (19180), such as tygontubing. Closed cell foam gaskets (19115) provide leakage protectionaround the sides of the sample. The test sample (19110) is compressed tothe caliper corresponding to the desired wet compression, which is setto 0.2 psi (about 1.4 kPa) unless otherwise mentioned. Liquid is allowedto flow through the sample (19110) to achieve steady state flow. Oncesteady state flow through the sample (19110) has been established,volumetric flow rate and pressure drop are recorded as a function oftime using a load cell (19198) and the differential pressure transducer(19197). The experiment can be performed at any pressure head up to 80cm water (about 7.8 kPa), which can be adjusted by the height adjustingdevice (19170). From these measurements, the flow rate at differentpressures for the sample can be determined.

The equipment is commercially available as a liquid Permeameter such assupplied by Porous Materials, Inc, Ithaca, N.Y. US under the designationPMI Liquid Permeameter, such as further described in respective usermanual of 2/97, and modified according to the present description. Thisequipment includes two Stainless Steel Frits as porous screens (19135),also specified in said brochure. The equipment consists of the samplecell (19120), inlet reservoir (19150), outlet reservoir (19154), andwaste reservoir (19156) and respective filling and emptying valves andconnections, an electronic scale, and a computerized monitoring andvalve control unit (19190).

The gasket material (19115) is a Closed Cell Neoprene Sponge SNC-1(Soft), such as supplied by Netherland Rubber Company, Cincinnati, Ohio,US. A set of materials with varying thickness in steps of {fraction(1/16)}″ (about 0.159 cm) should be available to cover the range from{fraction (1/16)}″-½″ (about 0.159 cm to about 1.27 cm ) thickness.

Further a pressurized air supply is required, of at least 60 psi (4.1bar), to operate the respective valves.

The test is then executed by the following steps:

1) Preparation of the test sample(s):

In a preparatory test, it is determined, if one or more members of thepresent invention are required, wherein the test as outlined below isrun at the lowest and highest pressure. The number of members is thenadjusted so as to maintain the flow rate during the test between 0.5cm³/seconds at the lowest pressure drop and 15 cm ³/second at thehighest pressure drop. The flow rate for the sample should be less thanthe flow rate for the blank at the same pressure drop. If the sampleflow rate exceeds that of the blank for a given pressure drop, morelayers should be added to decrease the flow rate. Sample size: Samplesare cut to 1″ (about 2.54 cm ) diameter, by using an arch punch, such assupplied by McMaster-Carr Supply Company, Cleveland, Ohio, US. Ifsamples have too little internal strength or integrity to maintain theirstructure during the required manipulation, a conventional low basisweight support means can be added, such as a PET scrim or net.

Thus, at least two samples (made of the required number of layers each,if necessary) are precut. Then, one of these is saturated in deionizedwater at the temperature the experiment is to be performed (70° F., (31°C.) unless otherwise noted).

The caliper of the wet sample is measured (if necessary after astabilization time of 30 seconds) under the desired compression pressurefor which the experiment will be run by using a conventional calipergauge (such as supplied by AMES, Waltham, Mass., US) having a pressurefoot diameter of 1⅛ (about 2.86 cm ), exerting a pressure of 0.2 psi(about 1.4 kPa) on the sample (19110), unless otherwise desired.

An appropriate combination of gasket materials is chosen, such that thetotal thickness of the gasketing foam (19115) is between 150 and 200% ofthe thickness of the wet sample (note that a combination of varyingthicknesses of gasket material may be needed to achieve the overalldesired thickness). The gasket material (19115) is cut to a circularsize of 3″ in diameter, and a 1 inch (2.54 cm ) hole is cut into thecenter by using the arch punch.

In case, that the sample dimensions change upon wetting, the sampleshould be cut such that the required diameter is taken in the wet stage.This can also be assessed in this preparatory test, with monitoring ofthe respective dimensions. If these change such that either a gap isformed, or the sample forms wrinkles which would prevent it fromsmoothly contacting the porous screens or frits, the cut diameter shouldbe adjusted accordingly.

The test sample (19110) is placed inside the hole in the gasket foam(19115), and the composite is placed on top of the bottom half of thesample cell, ensuring that the sample is in flat, smooth contact withthe screen (19135), and no gaps are formed at the sides.

The top of the test cell (19121) is laid flat on the lab bench (oranother horizontal plane) and all three caliper gauges (19145) mountedthereon are zeroed.

The top of the test cell (19121) is then placed onto the bottom part(19122) such that the gasket material (19115) with the test sample(19110) lays in between the two parts. The top and bottom part are thentightened by the fixation screws (19140), such that the three calipergauges are adjusted to the same value as measured for the wet sampleunder the respective pressure in the above.

2) To prepare the experiment, the program on the computerized unit(19190) is started and sample identification, respective pressure etc.are entered.

3) The test will be run on one sample (19110) for several pressurecycles, with the first pressure being the lowest pressure. The resultsof the individual pressure runs are put on different result files by thecomputerized unit (19190). Data are taken from each of these files forthe calculations as described below. (A different sample should be usedfor any subsequent runs of the material.)

4) The inlet liquid reservoir (19150) is set to the required height andthe test is started on the computerized unit (19190).

5) Then, the sample cell (19120) is positioned into the permeameter unitwith Quick Disconnect fittings (19189).

6) The sample cell (19120) is filled by opening the vent valve (19188)and the bottom fill valves (19184, 19186). During this step, care mustbe taken to remove air bubbles from the system, which can be achieved byturning the sample cell vertically, forcing air bubbles—if present—toexit the permeameter through the drain. Once the sample cell is filledup to the tygon tubing attached to the top of the chamber (19121), airbubbles are removed from this tubing into the waste reservoir (19156).

7) After having carefully removed air bubbles, the bottom fill valves(19184, 19186) are closed, and the top fill (19182) valve is opened, soas to fill the upper part, also carefully removing all air bubbles.

8) The fluid reservoir is filled with test fluid to the fill line(19152).

Then the flow is started through the sample by initiating thecomputerized unit (19190).

After the temperature in the sample chamber has reached the requiredvalue, the experiment is ready to begin.

Upon starting the experiment via the computerized unit (19190), theliquid outlet flow is automatically diverted from the waste reservoir(19156) to the outlet reservoir (19154), and pressure drop, andtemperature are monitored as a function of time for several minutes.

Once the program has ended, the computerized unit provides the recordeddata (in numeric and/or graphical form).

If desired, the same test sample can be used to measure the permeabilityat varying pressure heads, with there by increasing the pressure fromrun to run.

The equipment should be cleaned every two weeks, and calibrated at leastonce per week, especially the frits, the load cell, the thermocouple andthe pressure transducer, thereby following the instructions of theequipment supplier.

The differential pressure is recorded via the differential pressuretransducer connected to the pressure probes measurement points (19194,19196) in the top and bottom part of the sample cell. Since there may beother flow resistances within the chamber adding to the pressure that isrecorded, each experiment must be corrected by a blank run. A blank runshould be done at 10, 20, 30, 40, 50, 60, 70, 80 cm requested pressure,each day. The permeameter will output a Mean Test Pressure for eachexperiment and also an average flow rate.

For each pressure that the sample has been tested at, the flow rate isrecorded as Blank Corrected Pressure by the computerized unit (19190),which is further correcting the Mean Test Pressure (Actual Pressure) ateach height recorded pressure differentials to result in the CorrectedPressure. This Corrected Pressure is the DP that should be used in thepermeability equation below.

Permeability can then be calculated at each requested pressure and allpermeabilities should be averaged to determine the k for the materialbeing tested.

Three measurements should be taken for each sample at each head and theresults averaged and the standard deviation calculated. However, thesame sample should be used, permeability measured at each head, and thena new sample should be used to do the second and third replicates.

The measuring of the in-plane permeability under the same conditions asthe above described transplanar permeability, can be achieved bymodifying the above equipment such as schematically depicted in FIGS. 2Aand 2B showing the partly exploded, not to scale view of the sample cellonly. Equivalent elements are denoted equivalently, such that the samplecell of FIG. 2 is denoted (20210), correlating to the numeral (19110) ofFIG. 1, and so on. Thus, the transplanar simplified sample cell (19120)of FIG. 1 is replaced by the in-plane simplified cell (20220), which isdesigned so that liquid can flow only in one direction (either machinedirection or cross direction depending on how the sample is placed inthe cell). Care should be taken to minimize channeling of liquid alongthe walls (wall effects), since this can erroneously give highpermeability reading. The test procedure is then executed quiteanalogous to the transplanar test.

The sample cell (20220) is designed to be positioned into the equipmentessentially as described for the sample cell (20120) in the abovetransplanar test, except that the filling tube is directed to the inletconnection (20232) the bottom of the cell (20220). FIG. 2A shows apartly exploded view of the sample cell, and FIG. 2B a cross-sectionalview through the sample level.

The test cell (20220) is made up of two pieces: a bottom piece (20225)which is like a rectangular box with flanges, and a top piece (20223)that fits inside the bottom piece (20225) and has flanges as well. Thetest sample is cut to the size of 2″ in ×2″ in (about 5.1 cm by 5.1 cm )and is placed into the bottom piece. The top piece (20223) of the samplechamber is then placed into the bottom piece (20225) and sits on thetest sample (20210). An incompressible neoprene rubber seal (20224) isattached to the upper piece (20223) to provide tight sealing. The testliquid flows from the inlet reservoir to the sample space via Tygontubing and the inlet connection (20232) further through the outletconnection (20233) to the outlet reservoir. As in this test executionthe temperature control of the fluid passing through the sample cell canbe insufficient due to lower flow rates, the sample is kept at thedesired test temperature by the heating device (20226), wherebythermostated water is pumped through the heating chamber (20227). Thegap in the test cell is set at the caliper corresponding to the desiredwet compression, normally 0.2 psi (about 1.4 kPa). Shims (20216) rangingin size from 0.1 mm to 20.0 mm are used to set the correct caliper,optionally using combinations of several shims.

At the start of the experiment, the test cell (20220) is rotated 900(sample is vertical) and the test liquid allowed to enter slowly fromthe bottom. This is necessary to ensure that all the air is driven outfrom the sample and the inlet/outlet connections (20232/20233). Next,the test cell (20220) is rotated back to its original position so as tomake the sample (20210) horizontal. The subsequent procedure is the sameas that described earlier for transplanar permeability, i.e. the inletreservoir is placed at the desired height, the flow is allowed toequilibrate, and flow rate and pressure drop are measured. Permeabilityis calculated using Darcy's law. This procedure is repeated for higherpressures as well.

For samples that have very low permeability, it may be necessary toincrease the driving pressure, such as by extending the height or byapplying additional air pressure on the reservoir in order to get ameasurable flow rate. In plane permeability can be measuredindependently in the machine and cross directions, depending on how thesample is placed in the test cell.

What is claimed is:
 1. A liquid handling member for absorbing body liquids wherein said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) of at least 50 cm and in that said liquid handling member has a liquid permeability of at least 5 Darcy.
 2. A liquid handling member according to claim 1, wherein said liquid handling member has a liquid permeability of at least 10 Darcy.
 3. A liquid handling member for absorbing body liquids wherein said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) of at least 80 cm and in that said liquid handling member has a liquid permeability of at least 2 Darcy.
 4. A liquid handling member for absorbing body liquids wherein said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) of at least 80 cm and in that said liquid handling member has an absorption time to 80% of its capacity of less than 5 seconds.
 5. A liquid handling member according to claim 1 further having a capillary sorption absorption capacity at 100 cm absorption height of at least 5 g/g.
 6. A device for handling body liquids comprising a liquid handling member according to claim
 1. 7. An absorbent structures comprising a first region for acquisition/distribution of fluid, said first region comprising at least one member for acquiring and/or transporting liquid and a second region for storage of fluid, said second region comprising a liquid handling member wherein said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) of at least 50 cm and in that said liquid handling member has a liquid permeability of at least 5 Darcy.
 8. A device for handling body liquids comprising an absorbent structure according to claim
 7. 9. A device for handling body liquids according to claim 6, wherein said device is a disposable absorbent article.
 10. A device for handling body liquids according to claim 9, wherein said device is a disposable diaper. 